Subsea housing assembly

ABSTRACT

A subsea housing assembly, in particular for a subsea sensor, is provided. A subsea housing includes a first housing portion and a second housing portion. The first housing portion includes a first electrical connection for data communication and the second housing portion includes a second electrical connection for data communication. A wall provides separation between the first housing portion and the second housing portion of the subsea housing. An inductive coupler, that includes a first coupling section disposed in the first housing portion and a second coupling section disposed in the second housing portion, is provided. The inductive coupler is configured to provide inductive coupling across the wall for providing at least a data communication between the first and second electrical connections.

PRIORITY STATEMENT

The present application hereby claims priority under 35 U.S.C. §119 toEuropean patent application number EP 16179521.6 filed Jul. 14, 2016,the entire contents of which are hereby incorporated herein byreference.

FIELD

At least one embodiment of the present invention generally relates to asubsea housing assembly and/or to a subsea sensor.

BACKGROUND

Subsea sensors have several applications in subsea processingfacilities. Examples of subsea sensors include temperature sensors,absolute or line pressure sensors, differential pressure sensors and thelike. A sensor may for example be mounted to a pipe section, throughwhich a process fluid flows, such as a gas, a liquid, or a multiphasefluid (which can include gaseous, liquid and solid constituents). Inparticular in subsea applications, the pressure of such process fluidcan reach relatively large values, such as for example in excess of1,000 or 1,400 bar. When measuring parameters of such process fluid in asubsea environment, it has to be ensured that the process fluid does notleak into the seawater.

For this purpose, penetrators can be provided in subsea sensors that arecapable of withstanding such large pressures. As an example, a glasspenetrator may be employed that leads electrical connections to a sensorelement and provides glass to metal sealing, such penetrator beingcapable of withstanding relatively large pressure differences.

In these applications, it is generally required to maintain a certainminimum electrical resistance (insulation resistance, IR) between thesensor housing and the electrical conductor that is led through anopening in the housing by such penetrator, for example a resistance ofat least 1 GΩ. By taking up humidity, the resistance of such penetratormay drop below 1 GΩ. Furthermore, it is generally required to test suchbarriers to a pressure of 2.5 times of the maximum pressure.Accordingly, if such sensor is to be operated on a flow line whichtransports a process fluid at a pressure of about 1,400 bar, the testpressure would need to be on the order of about 3,500 bar. At suchpressures, the glass-to-metal seal provided by the above mentionedpenetrator may exceed its limits. Furthermore, when testing at such highpressures, especially under water, a low insulation resistance mayresult due to the above outlined taking up of humidity by the glass.Furthermore, an additional final treatment process, for example a dryingprocess, may be required before installing such sensors in order to meetthe specifications. Such process is time and cost intensive.

SUMMARY

Accordingly, the inventors have discovered that it is desirable toimprove the performance of such subsea sensors, in particular to allowsuch subsea sensor to be used with high pressure process fluids, whilemeeting all the specifications, such as the required insulationresistance, and providing the required operational safety.

Accordingly, the inventors recognize that there is a need forimprovements related to subsea sensors and in particular with respect tothe handling of such high process pressures.

The claims describe embodiments of the invention.

According to an embodiment of the invention, a subsea housing assemblyis provided. The subsea housing assembly comprises a subsea housing,wherein a first housing portion of the subsea housing comprises a firstelectrical connection for data communication, and wherein a secondhousing portion of the subsea housing comprises a second electricalconnection for data communication. A wall provides separation betweenthe first and second housing portions. The subsea housing assemblyfurther includes an inductive coupler that comprises a first couplingsection disposed in the first housing portion and a second couplingsection disposed in the second housing portion. The inductive coupler isconfigured to provide inductive coupling across the wall for providingat least a data communication between the first electrical connection inthe first housing portion and the second electrical connection in thesecond housing portion.

According to a further embodiment of the invention, a subsea sensorcomprising a subsea housing assembly in accordance with any of the abovedescribed configurations is provided. The subsea sensor may comprise asensor element that is disposed in the first housing portion. The firstelectrical connection may be configured for communicating with thesensor element (for example for transferring raw or processed sensordata). The second electrical connection may be configured to provide atleast a sensor output of the subsea sensor. As an example, sensor datafrom the sensor element may be communicated via the first electricalconnection, the inductive coupler and the second electrical connectionto an output of the subsea sensor.

It is to be understood that the features mentioned above and those yetto be explained below cannot only be used in the respective combinationsindicated, but also in other combinations or in isolation withoutleaving the scope of the present invention. In particular, it should beclear that the subsea housing assembly may be employed with subseadevices other than subsea sensor, such as a subsea electronic canister,subsea control unit/module or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention willbecome further apparent from the following detailed description read inconjunction with the accompanying drawings. In the drawings, likereference numerals refer to like elements.

FIG. 1 is a schematic diagram showing a subsea housing assembly and asubsea sensor according to an embodiment of the invention.

FIG. 2 is a schematic diagram showing a subsea sensor comprising asubsea housing assembly according to an embodiment of the invention.

FIG. 3 is a schematic diagram showing a subsea housing assembly mountedto a pipe section according to an embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In the following, embodiments of the invention are described in detailwith reference to the accompanying drawings. It is to be understood thatthe following description of the embodiments is given only for thepurpose of illustration and is not to be taken in a limiting sense. Itshould be noted that the drawings are to be regarded as being schematicrepresentations only, and elements in the drawings are not necessarilyto scale with each other. Rather, the representation of the variouselements is chosen such that their function and general purpose becomeapparent to a person skilled in the art.

The drawings are to be regarded as being schematic representations andelements illustrated in the drawings are not necessarily shown to scale.Rather, the various elements are represented such that their functionand general purpose become apparent to a person skilled in the art. Anyconnection or coupling between functional blocks, devices, components,or other physical or functional units shown in the drawings or describedherein may also be implemented by an indirect connection or coupling. Acoupling between components may also be established over a wirelessconnection. Functional blocks may be implemented in hardware, firmware,software, or a combination thereof.

Various example embodiments will now be described more fully withreference to the accompanying drawings in which only some exampleembodiments are shown. Specific structural and functional detailsdisclosed herein are merely representative for purposes of describingexample embodiments. Example embodiments, however, may be embodied invarious different forms, and should not be construed as being limited toonly the illustrated embodiments. Rather, the illustrated embodimentsare provided as examples so that this disclosure will be thorough andcomplete, and will fully convey the concepts of this disclosure to thoseskilled in the art. Accordingly, known processes, elements, andtechniques, may not be described with respect to some exampleembodiments. Unless otherwise noted, like reference characters denotelike elements throughout the attached drawings and written description,and thus descriptions will not be repeated. The present invention,however, may be embodied in many alternate forms and should not beconstrued as limited to only the example embodiments set forth herein.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections, should not be limited by these terms. These terms areonly used to distinguish one element from another. For example, a firstelement could be termed a second element, and, similarly, a secondelement could be termed a first element, without departing from thescope of example embodiments of the present invention. As used herein,the term “and/or,” includes any and all combinations of one or more ofthe associated listed items. The phrase “at least one of” has the samemeaning as “and/or”.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below,” “beneath,” or“under,” other elements or features would then be oriented “above” theother elements or features. Thus, the example terms “below” and “under”may encompass both an orientation of above and below. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly. Inaddition, when an element is referred to as being “between” twoelements, the element may be the only element between the two elements,or one or more other intervening elements may be present.

Spatial and functional relationships between elements (for example,between modules) are described using various terms, including“connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitlydescribed as being “direct,” when a relationship between first andsecond elements is described in the above disclosure, that relationshipencompasses a direct relationship where no other intervening elementsare present between the first and second elements, and also an indirectrelationship where one or more intervening elements are present (eitherspatially or functionally) between the first and second elements. Incontrast, when an element is referred to as being “directly” connected,engaged, interfaced, or coupled to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between,” versus “directly between,” “adjacent,” versus“directly adjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments of the invention. As used herein, the singular forms “a,”“an,” and “the,” are intended to include the plural forms as well,unless the context clearly indicates otherwise. As used herein, theterms “and/or” and “at least one of” include any and all combinations ofone or more of the associated listed items. It will be furtherunderstood that the terms “comprises,” “comprising,” “includes,” and/or“including,” when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist. Also, the term “exemplary” is intended to refer to an example orillustration.

When an element is referred to as being “on,” “connected to,” “coupledto,” or “adjacent to,” another element, the element may be directly on,connected to, coupled to, or adjacent to, the other element, or one ormore other intervening elements may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to,”“directly coupled to,” or “immediately adjacent to,” another elementthere are no intervening elements present.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Before discussing example embodiments in more detail, it is noted thatsome example embodiments may be described with reference to acts andsymbolic representations of operations (e.g., in the form of flowcharts, flow diagrams, data flow diagrams, structure diagrams, blockdiagrams, etc.) that may be implemented in conjunction with units and/ordevices discussed in more detail below. Although discussed in aparticularly manner, a function or operation specified in a specificblock may be performed differently from the flow specified in aflowchart, flow diagram, etc. For example, functions or operationsillustrated as being performed serially in two consecutive blocks mayactually be performed simultaneously, or in some cases be performed inreverse order. Although the flowcharts describe the operations assequential processes, many of the operations may be performed inparallel, concurrently or simultaneously. In addition, the order ofoperations may be re-arranged. The processes may be terminated whentheir operations are completed, but may also have additional steps notincluded in the figure. The processes may correspond to methods,functions, procedures, subroutines, subprograms, etc.

Specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing example embodiments of thepresent invention. This invention may, however, be embodied in manyalternate forms and should not be construed as limited to only theembodiments set forth herein.

Although described with reference to specific examples and drawings,modifications, additions and substitutions of example embodiments may bevariously made according to the description by those of ordinary skillin the art. For example, the described techniques may be performed in anorder different with that of the methods described, and/or componentssuch as the described system, architecture, devices, circuit, and thelike, may be connected or combined to be different from theabove-described methods, or results may be appropriately achieved byother components or equivalents.

According to an embodiment of the invention, a subsea housing assemblyis provided. The subsea housing assembly comprises a subsea housing,wherein a first housing portion of the subsea housing comprises a firstelectrical connection for data communication, and wherein a secondhousing portion of the subsea housing comprises a second electricalconnection for data communication. A wall provides separation betweenthe first and second housing portions. The subsea housing assemblyfurther includes an inductive coupler that comprises a first couplingsection disposed in the first housing portion and a second couplingsection disposed in the second housing portion. The inductive coupler isconfigured to provide inductive coupling across the wall for providingat least a data communication between the first electrical connection inthe first housing portion and the second electrical connection in thesecond housing portion.

By providing a subsea housing assembly with such inductive coupler, adata communication can be established through the wall of the subseahousing which allows for example a better sealing of the first housingportion. For example when used in a subsea sensor, the first housingportion can comprise the sensor element, and the wall can provide apressure barrier for the process fluid pressure so that the pressure canbe confined to within the first housing portion. The data communicationmay for example include a communication of analog or digital sensorvalues or readings, it may for example include raw or processed sensordata.

By providing the inductive coupler, it is not necessary to provide glasspenetrators including a glass to metal sealing. Accordingly, problemsassociated with large pressure differences across such penetrators andreduced insulation resistance of such penetrators may be avoided. Therisk of a leakage may thus be reduced. Furthermore, since the separationis provided by the wall, and no penetrator is required, the testingstandard may only require lower test pressures, thus facilitating themeeting of the specifications by a respective device comprising suchsubsea housing assembly.

In an embodiment, the wall may be a metal wall. In an embodiment, thebarrier provided by the first housing portion and the wall may notinclude non-metallic parts. In particular, the sealing may be effectedby metal-to-metal seals, and may not include glass-to-metal seals. Thetest pressure for metal barriers is generally lower than that requiredfor non-metallic barriers, so that a safer sealing may be achieved andlower test pressures can be employed.

In an embodiment, the wall is a pressure barrier configured to resist apredetermined minimum pressure difference across the wall. Such minimumpressure difference may for example be at least 1.5 times or even 2.5times the expected process pressure (the pressure difference may becalculated with respect to zero or 1 bar pressure or with respect to aprevailing subsea pressure, depending on the application and theconfiguration of the second housing portion).

The inductive coupler may furthermore be configured to inductivelysupply electrical power from the electrical connection in the secondhousing portion to the electrical connection in the first housingportion. Accordingly, a sensor element disposed in the first housingportion may thus be supplied with electrical power.

In some configurations, a single electrical line may be provided forpower supply and data communication, for example by providing arespective modulation on the power line. In other embodiments, separatelines may be provided and may be part of the respective electricalconnection, for example dedicated lines for power supply and datacommunication. In some embodiments, the sensor may only be a passivesensor, and only the electrical power required to read such passivesensor may be transmitted by means of the inductive coupler. In otherapplications, further electric and/or electronic components may beprovided in the first housing portion, for example for operating thesensor element or processing sensor data. The inductive couplerpreferably comprises the first and second coupling sections whichprovide both inductive coupling for data communication and powertransfer. In other embodiments, the inductive coupler may comprisefurther coupling sections, for example for separately transferringelectrical power and communication signals.

In an embodiment, the first housing portion comprises at least a firstchamber. The chamber may be a pressure resistant chamber in which apredetermined pressure, in particular a pressure of less than 10 bar,less than 5 bar or less than 1.5 bar is maintained when the subseahousing assembly is installed subsea. Accordingly, conventional electricand electronic components may be used in such chamber. The chamber maybe filled with a gas, such as air or nitrogen or another gas mixture. Atleast the first coupling section may be disposed in the first chamber.The first chamber may be sealed in a liquid tight manner. In particular,the first chamber may be hermetically sealed.

In other applications, the first chamber may be a pressure compensatedchamber, the inner pressure of which is balanced to an ambient pressure,such as the surrounding subsea pressure when installed subsea.

The first housing portion may for example comprise a sensor assemblyincluding diaphragms, such as a process diaphragm and a sensordiaphragm, a sensor element, medium filled channels or the like and mayfurther include a first pressure barrier that provides separationbetween the pressure prevailing in such medium filled channels and thefirst chamber. As an example, a process diaphragm may transmit thepressure of the process fluid to such medium (e.g. oil) present in thechannels, which in turn applies the pressure to a sensor element.Accordingly, if such first pressure barrier fails, and process fluid orprocess fluid pressure is transmitted into the first chamber, suchfluid/pressure can be confined to within the first housing portion bymeans of the wall, which constitutes a second pressure barrier.

The first housing portion may be sealed against a metal body by means ofa metal seal, in particular a metal gasket. As an example, the subseahousing assembly may be part of a subsea sensor, and the first housingportion may be sealed against a pipe section, for example a pipelinesection or a flow duct in a Christmas tree or the like. The firsthousing portion may comprise a mounting flange for mounting the subseahousing assembly to such metal body.

In an embodiment, the subsea housing is a subsea housing of a subseaelectrical device, and the first housing portion may comprise at least afirst chamber, wherein electric and/or electronic components of thesubsea electrical device are disposed in the first chamber. Suchcomponents may for example include sensor electronic components used tooperate a sensor element or process sensor data; in other applications,such as when used with a subsea control module, the first chamber maycomprise control electronics or the like.

In an embodiment, the second housing portion comprises at least a secondchamber. The second chamber may be a pressure compensated chamber thatis pressure balanced against an ambient pressure, in particular againstthe seawater pressure when installed subsea. By making use of suchpressure compensated chamber, the sealing of the chamber may befacilitated since the pressure difference across the walls of thechamber can be kept low. Furthermore, the walls of the second housingportion may thus not need to be capable of withstanding the relativelyhigh subsea pressures, so that a more compact and lightweight subseahousing assembly can be achieved.

The second coupling section may be disposed in the second chamber. Thesecond chamber may be filled with an (substantially) incompressiblemedium, such as a liquid or gel, in particular a dielectric liquid.Examples are oil or Midel (synthetic ester-based liquid).

In an embodiment, the second housing portion comprises a pressurecompensator providing the pressure compensation. Additionally oralternatively, the second housing portion may be connected to a subseacable in form of a medium (in particular oil) filled hose. The secondchamber may be pressure compensated via the oil filled hose. As anexample, there may be a flow communication between the second chamberand an inner volume of the medium filled hose so that the pressureinside the second chamber can be equalized. In other embodiments,separation between these volumes may be provided, for example by meansof a membrane, a bellows or the like.

In an embodiment, the wall is a pressure barrier providing separationbetween a first chamber in the first housing portion and a secondchamber in the second housing portion. The first chamber may be apressure resistant chamber or pressure compensated chamber, and thesecond chamber may be a pressure resistant chamber or a pressurecompensated chamber. Preferably, the first chamber is pressure resistantwhereas the second chamber is pressure compensated, but it should beclear that in other embodiments, two pressure compensated or twopressure resistant chambers may be provided in the subsea housingassembly. As an example, the second chamber may comprise a penetratorproviding a pressure barrier between the inside of the second chamberand a medium (or oil) filled hose.

In an embodiment, the wall is integrally formed with a first housingbody of the first housing portion. The first housing body may forexample be shaped like a metal canister having an opening through whichpart of a sensor extends and that is sealed to a metal body, such as apipe section or the like (where the subsea sensor is installed). Thefirst housing body may be a single piece metal body.

In other embodiments, the first housing portion comprises plural housingparts, and the housing parts are preferably sealed to each other bymetal seals. It is noted that the expression “single peace metal body”does not imply that the housing portion cannot comprise further elementsmounted to such single peace metal body, but it means that the part ofthe first housing portion that includes the wall provides the pressurebarrier and that is sealed to, e.g., a pipe section (or another part ofthe first housing portion) is formed integrally from a single piece ofmaterial. A safe and reliable pressure barrier within the subsea housingassembly may thus be obtained, which may be capable of withstandinglarge to very large pressure differences, such as between the processfluid pressure and the surrounding ambient pressure.

In an embodiment, the second housing portion is fixedly mounted to thefirst housing portion. As an example, the second housing portion may bebolted to or welded to the first housing portion. A reliable connectionbetween the first and second housing portions may thus be achieved.

As an example, the second housing portion may comprise an enclosurehaving an opening. The second housing portion may be attached to thefirst housing portion such that the opening is closed and sealed by thefirst housing portion. The opening may for example be at least partlyclosed by the wall across which the inductive coupling is provided. Thesecond coupling section may be located in or adjacent to such opening.Accordingly, assembly of the subsea housing assembly may be facilitated,since when mounting the second housing portion to the first housingportion, no electrical connections have to be established.

Sealing between the first and second housing portions may be provided byO-ring seals, for example two elastomeric O-ring seals. For example whenthe second chamber is a pressure compensated chamber, such seals mayprovide reliable sealing since the differential pressure is relativelylow. Mounting the first and second housing portions together generallyoccurs topside, i.e. the first and second housing portions may not beconnectable in a subsea environment.

In an embodiment, the first coupling section and/or the second couplingsection of the inductive coupler are provided by a respective coil. Thecoil is connected to the respective electrical connection. As anexample, the coil in the second housing section may be driven by an ACcurrent that can be modulated for data communication. The resultingelectromagnetic field can induce a current in the coil of the firstcoupling section in the first housing portion. Electrical power and datacommunication signals (which can include control signals) may thus betransferred into the first housing portion. Similarly, a modulatedcurrent can be provided to the coil of the first coupling section, whichinduces a respective current in the second coupling section, for examplefor transferring sensor data or the like.

In an embodiment, the first coupling section comprises an inner coil andthe second coupling section comprises an outer coil, or vice versa. Theouter coil may at least partly surround the inner coil. At least part ofthe wall may extend between the inner coil and the outer coil. As anexample, the wall may be shaped so as to extend around the inner coilsuch that it surrounds the inner coil for at least part of its width,and covers one side of the inner coil. Around this wall section, theouter coil may extend.

In an embodiment, the first coupling section comprises a first coil andthe second coupling section comprises a second coil, and the first andsecond coils may be arranged an opposite sides of the wall. The coilsmay be arranged substantially coaxially, they may be arranged coaxially.

In some embodiments, the coils of the first and second coupling sectionsmay have substantially the same diameter, and the wall may comprise aplanar wall section arranged between the coils.

Preferably, the coil of the first coupling section is an inner coil, andthe coil of the second coupling section is an outer coil that extendsaround the inner coil.

According to a further embodiment of the invention, a subsea sensorcomprising a subsea housing assembly in accordance with any of the abovedescribed configurations is provided. The subsea sensor may comprise asensor element that is disposed in the first housing portion. The firstelectrical connection may be configured for communicating with thesensor element (for example for transferring raw or processed sensordata). The second electrical connection may be configured to provide atleast a sensor output of the subsea sensor. As an example, sensor datafrom the sensor element may be communicated via the first electricalconnection, the inductive coupler and the second electrical connectionto an output of the subsea sensor.

As mentioned further above, the first housing portion may comprise afurther pressure barrier, and the sensor element may for example bearranged in a region where it is exposed to the pressure of a processfluid. The housing may comprise a first chamber (disposed behind thefirst pressure barrier) comprising sensor related electronics, andfurther comprising a transmitter/receiver for providing datacommunication by means of the inductive coupler.

In an embodiment, the first chamber and/or the second chamber comprisesa receiver and a transmitter, or a transceiver, for providing datacommunication via the inductive coupler.

In an embodiment, the first housing portion comprises a sensor assemblythat includes a first pressure barrier between a process fluid to beprobed by the subsea sensor and a first chamber in the first housingportion. The wall may constitute a second pressure barrier. Accordingly,if the first pressure barrier should fail, the pressure of a processfluid may effectively be confined to within the first housing portion.

In the following, embodiments of the invention will be described indetail with reference to the accompanying drawings. It is to beunderstood that the following description of the embodiments is givenonly for the purpose of illustration and is not to be taken in alimiting sense. The drawings are to be regarded as being schematicrepresentations only, and elements in the drawings are not necessarilyto scale with each other. Rather, the representation of the variouselements is chosen such that their function and general purpose becomeapparent to a person skilled in the art.

FIG. 1 is schematic drawing showing a subsea housing assembly 100 thatis part of a subsea sensor 200. The subsea housing assembly 100 includesa first housing portion 10 and a second housing portion 20. The firsthousing portion 10 includes a first housing body 12 and a first chamber11. The second housing portion 20 includes a second housing body 22 anda second chamber 21. The first and second housing bodies 12, 22 includeflanges 18, 28, respectively, by means of which they are fixedlyattached to each other. In the present example, both housing portionsare bolted together.

The first housing body 12 substantially surrounds the first chamber 11.In particular, the first housing portion 10 includes a wall 30 thatprovides a pressure barrier. This allows application of a high pressuredifference across the walls of the first housing body 12. In particular,and as illustrated in FIG. 1, the wall 30 can be formed integrally, i.e.as part of the first housing body 12. In such configuration, no sealsare required between the wall 30 and the remaining portions of the firsthousing body 12. The wall 30 provides separation between the firstchamber 11 and the second chamber 21. Accordingly, a save and reliablesealing can be provided between the first and second chambers 11, 21that is capable of withstanding high pressure differences, for examplein excess of 1,000 or even 2,000 bar.

At the other end, the first housing portion 10 may simply be closed, forexample by means of a closing plate or the like. Such configuration maybe employed when the subsea housing assembly 100 is used for a subseacanister, such as a subsea electronic canister or a control canister orcontrol module. In the embodiment of FIG. 1, the subsea housing assembly100 is used for a subsea sensor 200, and a further pressure barrier(first pressure barrier) 17 is provided in the first housing portion 10.The first pressure barrier 17 provides sealing of the first chamber 11towards a part of the first housing portion 10 in which a sensor element61 is located and exposed to high pressures, such as the high pressureof a process fluid. Note that such exposure may be a direct exposure, oran indirect exposure, for example via a respective process diaphragm anda pressure transmission fluid such as oil or the like.

When embodied as subsea sensor as in FIG. 1, the first chamber 11 maycomprise sensor electronics 62, such as control electronics, dataprocessing electronics and the like. The first chamber 11 may be apressure resistant chamber in which a predefined pressure is maintained,even when the subsea housing assembly 100 is installed at a subsealocation. Such pressure may be a pressure below 10 bar, it maypreferably be a pressure below 5, or even below 1.5 bar. A close toatmospheric pressure may prevail in the first chamber 11, which may thusbe termed an atmospheric chamber. Chamber 11 may be filled with a gas,such as nitrogen, or a gas mixture, such as air or a mixture of nitrogenwith other gasses. It may thus be possible to operate conventionalelectric and electronic components within chamber 11.

Accordingly, in the configuration of the subsea housing assembly asillustrated in FIG. 1, high pressures, such as of a process fluid, caneffectively be confined to within the first chamber 11, even if thefirst pressure barrier 17 fails. The first pressure barrier 17 may forexample comprise a feed through for an electric connection to the sensorelement 61, or the sensor element 61 may itself be configured so as toconstitute a pressure barrier. Under certain conditions, such pressurebarrier may fail, thus allowing high pressure fluid to enter chamber 11.Since wall 30 is provided that does not comprise any feed through, thepressure can be confined effectively within the first housing portion10.

For providing a data communication with an electronic component withinthe first housing section 10, an inductive coupler 50 comprising a firstcoupling section 51 and a second coupling section 52 is provided. Thefirst coupling section 51 is disposed in the first chamber 11 andconnected to an electrical connection 15 that provides at least datacommunication, in particular with the sensor element 61 or the sensorelectronics 62 in the example of FIG. 1. The second coupling section 52is disposed in the second chamber 21 and is connected to a secondelectrical connection 25 in the second housing portion 20. The inductivecoupler 50 provides at least data communication between the first andsecond electrical connections 15, 25 across the wall 30. Besidestransmitting data communications, the coupler 50 is further moreconfigured to transfer power from the electrical connection 25 to theelectrical connection 15.

The first and second coupling sections 51, 52 may for example beimplemented as coils. An alternating current (AC) provided to the secondcoupling section 52 may for example induce a current in the firstcoupling section 51, which provides power to electric and electroniccomponents comprised in the first housing portion 10. This way, sensorelectronics 62 and sensor element 61 may be powered. For datatransmission, modulation may be provided. As an example, the currentapplied to the coil 52 may be modulated, and such modulation will leadto a modulation of the current induced in the first coupling section 51.For this purpose, a receiver/transmitter 56 can be provided in thesecond housing portion 20 and can be coupled to the second electricalconnection 25. Unit 56 can include a receiver and a transmitter, and itmay modulate control signals received on line 41 for transmission viathe inductive coupler 50, and it may demodulate signals received fromthe second coupling section 52 for further transmission via the line 41.Note that the transmitter/receiver 56 may also be located at a differentposition, for example at the other end of line 41, topside or the like.

Similarly, a transmitter/receiver 55 is provided in the first housingportion 10 in chamber 11 and is connected to the first electricalconnection 15 and the first coupling section 51. Unit 55 may for exampledetect a modulation of a current received from the first couplingsection 51 and may provide corresponding control signals to the sensorelectronics 62. Unit 55 may further receive sensor data from the sensorelectronics 62 and may modulate such sensor data onto a signal that isprovided to the first coupling section 51, so that a current is inducedin the second coupling section 52 that is detected and demodulated bytransmitter/receiver unit 56. Accordingly, data recorded by the sensorelement 61 can be communicated on line 41, without requiring penetrationof wall 30 that provides the secondary pressure barrier.

The inductive coupler including the first and second coupling sections51, 52 may also be implemented differently. As an example, a GHz ormicrowave transmitter/receiver may be provided for transmitting powerand communication signals across the wall 30. Furthermore, the inductivecoupler may comprise plural coupling sections, for example somededicated to the transfer of electrical power and others dedicated tothe transfer of data communications. Preferably, power and datacommunications are transmitted by the same coupling sections.

As the pressure is confined to within the first housing portion 10 bymeans of wall 30, the sealing of the second housing portion 20 isfacilitated. In particular, the second chamber 21 can be a pressurecompensated chamber the pressure of which is balanced to the surroundingambient pressure, in particular the subsea pressure when the housingassembly 100 is installed subsea. The differential pressure across thewalls of the second housing body 22 is accordingly relatively low. Inthe example of FIG. 1, the housing body 22 has an opening in which thesecond coupling section 52 is located. This opening is sealed againstthe first housing body 12, for example by means of O-ring seals 29.Double seals are preferably provided.

The second chamber 21 can be filled with a substantially incompressiblemedium, in particular a dielectric liquid or gel, such as oil or thelike. The electric and electronic components of the unit 56 can beadapted to operate in such environment, or, as mentioned above, unit 56may be located outside the chamber 21, for example in a subsea canisterto which the sensor 200 is connected or topside. Pressure compensationcan occur by means of a dedicated pressure compensator forming part ofthe subsea housing assembly 100 (not shown). In other embodiments, thesubsea housing assembly 100 may be connected to a subsea cable in formof an oil filled hose, wherein the inner volume of such hose is filledwith a dielectric liquid (in particular oil) and is pressure compensatedagainst the ambient environment due to the flexibility of the hose.Pressure compensation of the second chamber 21 can occur via such hose,for example by allowing a flow communication through the opening 26between the inner volume of the hose and the chamber 21, or by providingsome pressure transmitting element in the opening, such as a membrane orbellows.

In other configurations the second chamber 21 can be a pressureresistant chamber. As an example, a predefined pressure below 10 bar,preferably below 5 bar or below 1.5 bar, such as close to atmosphericpressure may be maintained in chamber 21. For this purpose, a penetratorproviding a pressure barrier can be provided in the opening 26. Sincesuch penetrator has to withstand the differential pressure between theinterior pressure of chamber 21 and the external subsea pressure wheninstalled subsea, the pressure difference is relatively low compared tothe pressure difference that can prevail when a barrier is exposed tothe pressure of process fluid, such as the barrier provided by wall 30.

The second housing portion 20 may for example comprise a fitting orconnector for providing a connection to a subsea cable. In otherconfigurations, a further unit, such as a control module or the like,may be mounted directly to the subsea housing assembly 100.

The first coupling section 51 and the second coupling section 52 can bemounted fixedly to their respective first or second housing bodies 12,22, they may for example be welded. Furthermore, by providing theinductive coupler 50, problems related to insulation resistant may beovercome. In particular, insulation resistance would in such case bemeasured between the metal cage provided by the first and second housingbodies 12, 22 and the respective coupling section 51, 52, so thatinsulation resistance can be kept high. In particular, since no glasspenetrators are used, the insulation resistance can also be maintainedduring high pressure testing.

FIG. 2 illustrates a further embodiment of a subsea housing assembly 100which forms part of another embodiment of a subsea sensor 200.Accordingly, the explanations given above with respect to FIG. 1 areequally applicable to the embodiment of FIG. 2, and only the differencesare explained in more detail hereinafter. The first housing portion 10is provided with a seal 19 for sealing against a subsea device, inparticular a metal body, such as a pipe section. The seal 19 ispreferably provided in form of a metal seal, in particular a metalgasket.

In the embodiment of FIG. 2, the first coupling section 51 is providedin form of an inner coil, and the second coupling section 52 is providedin form of an outer coil that extends around the inner coil. Both coilsare arranged coaxially. The wall 30 extends between the first and secondcoupling sections 51, 52. Accordingly, in the example of FIG. 2, thewall 30 is curved and extends around the inner coil. Again, wall 30 isformed integrally with the first housing body 12 of the first housingportion 10. By such configuration, an efficient transfer of datacommunication and electrical power may be achieved while maintaining aneffective and secure pressure barrier between the first and secondchambers 11, 21.

In the embodiment of FIG. 2, the second housing body 22 has a smallerdiameter portion that is attached to a larger diameter portion (flange18) of the first housing body 12. As an example, the second housing body22 may be screwed into the first housing body 12. Between both housingbodies, seals 29 are provided, which can be in the form of elastomericor metal O-ring seals. The opening 26 has the form of a fitting, intowhich the end of a subsea cable, such as an oil filled hose, can bescrewed or otherwise be attached. As an example, it may be an MKIIfitting. A mounting flange 16 is provided for mounting the subseahousing assembly 100 to the other subsea device, in particular pipesection.

In FIG. 2, the electrical connections 15, 25 as well as other electricaland electronic components are emitted for the purpose of a clearpresentation. It should be clear that these components may certainly bepresent.

In FIG. 3, a further embodiment of a subsea housing assembly 100 that ispart of a embodiment of a subsea sensor 200 is illustrated. Theexplanations given further above with respect to FIGS. 1 and 2 areequally applicable to the embodiment of FIG. 3. In FIG. 3, the subseahousing assembly 100 is mounted to a subsea device 80 in form of a pipesection through which a process fluid flows. As can be seen, by means ofthe mounting flange 16, the first housing body 12 is pressed against thesubsea device 80 and sealed by means of the seal 19, which can be ametal gasket. Note that two seals 19 may be provided to provide a doublebarrier.

Sensor element 61 may for example measure temperature and/or pressure ofthe process fluid flowing through the pipe section, and respectivereadings may be modulated and transmitted by the transmitter/receiver 55via the inductive coupler 50.

To the port opening 26 of the second housing portion 20, a subsea cablein form of an oil filled hose 40 is mounted. Note that the subsea cablemay form part of the subsea sensor 200, and that a (wet mate or drymate) connector may be provided at the other end of the subsea cable 40for connecting the sensor 200 to another subsea device or to a topsideinstallation. In the example of FIG. 3, the line 41 of the subsea cable40 is directly connected to the electrical connection 25 and the secondcoupling section 52. It should be clear that in other embodiments,further electric and electronic components, such as thetransmitting/receiving unit 56, can be provided. Again, it is noted thatthe opening 26 may in some embodiments allow a flow communicationbetween the interior of subsea cable 40 and the second chamber 21, whilein other embodiments, separation may be provided. Such separation can beprovided by a pressure transmitting element such as a membrane, or bymeans of a penetrator which allows the maintaining of a pressuredifference across the opening 26.

The subsea housing assembly 100 is described above with respect to theuse in a subsea sensor 200, yet it should be clear that it may also beused in other applications, in particular where the integrity of apressure barrier is of importance, for example for protecting electricand electronic components. Such applications may include the applicationin a subsea control unit where the integrity of a one atmosphericchamber needs to be ensured. Other applications are conceivable.

While specific embodiments are disclosed herein, various changes andmodifications can be made without departing from the scope of theinvention. The present embodiments are to be considered in all respectsas illustrative and non restrictive, and all changes coming within themeaning and equivalency range of the appended claims are intended to beembraced therein.

What is claimed is:
 1. A subsea housing assembly, comprising: a subseahousing, the subsea housing including a first housing portion, the firsthousing portion including a first electrical connection for datacommunication, and a second housing portion, the second housing portionincluding a second electrical connection for data communication; a wallto provide separation between the first housing portion and the secondhousing portion of the subsea housing, the wall being integrally formedwith a first housing body of the first housing portion; and an inductivecoupler including a first coupling section disposed in the first housingportion and a second coupling section disposed in the second housingportion, the inductive coupler being configured to provide inductivecoupling across the wall to provide at least a data communicationbetween the first electrical connection in the first housing portion andthe second electrical connection in the second housing portion.
 2. Thesubsea housing assembly of claim 1, wherein the wall is a pressurebarrier configured to resist a minimum pressure difference across thewall.
 3. The subsea housing assembly of claim 1, wherein the inductivecoupler is further configured to inductively supply electrical powerfrom the electrical connection in the second housing portion to theelectrical connection in the first housing portion.
 4. The subseahousing assembly of claim 1, wherein the first housing portion includesat least a first chamber, the first chamber being a pressure resistantchamber in which a pressure is maintained when the subsea housingassembly is installed subsea.
 5. The subsea housing assembly of claim 1,wherein the subsea housing is a subsea housing of a subsea electricaldevice, the first housing portion including at least a first chamber,and wherein at least one of electric and electronic components of thesubsea electrical device are disposed in the first chamber.
 6. Thesubsea housing assembly of claim 1, wherein the second housing portionincludes at least a second chamber, the second chamber being a pressurecompensated chamber that is pressure balanced against an ambientpressure.
 7. The subsea housing assembly of claim 6, wherein the secondhousing portion includes a pressure compensator providing pressurecompensation.
 8. The subsea housing assembly of claim 1, wherein thewall is a pressure barrier providing separation between a first chamberin the first housing portion and a second chamber in the second housingportion, the first chamber being a pressure resistant chamber or apressure compensated chamber, and the second chamber being a pressureresistant chamber or a pressure compensated chamber.
 9. The subseahousing assembly of claim 1, wherein the second housing portion isfixedly mounted to the first housing portion.
 10. The subsea housingassembly of claim 1, wherein the second housing portion includes asecond housing body including an opening, the second housing portionbeing attached to the first housing portion such that the opening isclosed and sealed by the first housing portion, and wherein the openingis at least partly closed by the wall across which the inductivecoupling is provided.
 11. The subsea housing assembly of claim 1,wherein the first coupling section of the inductive coupler and thesecond coupling section of the inductive coupler are each provided by arespective coil.
 12. The subsea housing assembly of claim 1, wherein thefirst coupling section includes an inner coil and the second couplingsection includes an outer coil, the outer coil at least partlysurrounding the inner coil and at least part of the wall extendingbetween the inner coil and the outer coil.
 13. The subsea housingassembly of claim 1, wherein the first coupling section includes a firstcoil and the second coupling section includes a second coil, the firstand second coils being arranged on opposite sides of the wall and thefirst and second coils being arranged substantially coaxial.
 14. Asubsea sensor, comprising: the subsea housing assembly of claim 1; asensor element disposed in the first housing portion, the firstelectrical connection being configured for providing communication withthe sensor element and the second electrical connection being configuredto provide at least a sensor output of the subsea sensor.
 15. A method,comprising: mounting the subsea sensor of claim 14 to a subsea device inform of a pipe section through which a process fluid flows.
 16. Thesubsea housing assembly of claim 1, wherein the first housing body is asingle piece metal body.
 17. The subsea housing assembly of claim 4,wherein the pressure is a pressure of less than 10 bar.
 18. The subseahousing assembly of claim 1, wherein the second housing portion includesat least a second chamber, the second chamber being a pressurecompensated chamber that is pressure balanced against a seawaterpressure when installed subsea.
 19. The subsea housing assembly of claim6, wherein the second housing portion is connected to a subsea cable inform of a medium filled hose, the second chamber being pressurecompensated via the medium filled hose.
 20. The subsea housing assemblyof claim 9, wherein the second housing portion is screwed to the firsthousing portion or welded to the first housing portion.
 21. The subseahousing assembly of claim 1, wherein at least one of the first couplingsection of the inductive coupler and the second coupling section of theinductive coupler is provided by a coil.
 22. The subsea housing assemblyof claim 1, wherein the first coupling section includes an outer coiland the second coupling section includes an inner coil, the outer coilat least partly surrounding the inner coil and at least part of the wallextending between the inner coil and the outer coil.
 23. A subseasensor, comprising: the subsea housing assembly of claim 2; a sensorelement disposed in the first housing portion, the first electricalconnection being configured for providing communication with the sensorelement and the second electrical connection being configured to provideat least a sensor output of the subsea sensor.
 24. A subsea sensor,comprising: the subsea housing assembly of claim 3; a sensor elementdisposed in the first housing portion, the first electrical connectionbeing configured for providing communication with the sensor element andthe second electrical connection being configured to provide at least asensor output of the subsea sensor.